Ever since school/work activities started requiring focus on my part, I've been easily distracted by a song playing on repeat in my head. It's usually a song I like at the moment, or one that's popular on the radio.

I can manage random thoughts coming through my mind and reject them, but I am almost never able to get rid of the songs... I would try singing something else in order to forget about the first song, but it usually ends up in a messy battle of songs in my head, which cancels any attempt to focus.

It's a real problem in my quest for lucid dreaming, since most of the techniques require some kind of focus...
Has anyone experienced something similar?